Inductance



Jab. 22, 1929. 1,699,661

G. A. FREEBURG I NDUC TANCE Filed Oct. 1925 3 Sheets-Sheet 1 Gear eflif'reebu Jan. 22, 1929.

5 Sheets-Sheet 2 G. A. FREEBURG Filed Oct. 1925 f f i I I J I 34 V1.

f Gas- 07i Cry/J Jan. 22, 1929.

G.A.FREEBURG INDUCTANCE Filed Oct. 1, 1925 Patented Jan. 22, 1929.

GEORGE A. FREEBURG, OF ELGIN, ILLINOI IIS.

INDUCTANCE.

Application filed October This invention has to do with certain improvements in inductance coils and the like. it has to do especially with in'iprovements in inductance coiis for radio and other similar high frequency work. Nevertheless, it will be understood that the features of the invention may also be used in connection with coils for other classes of work than that above referred to.

The main object of the invention is to pro- \ido a coil of the general torm ot a toroid, so as to thereby largely eliminate outside or cri interference between the coil and other outside devices. 'loroid coiis are well known and understood in the radio field, but the coil herein disclosed presents certain new features of construction and the method of construction is also novel.

One ot the objects oi the invention is to provide a coil of the general form of a toroid and in which the various turns are so crisscrossed and related with respect to each other as to largely eliminate intcrturn capacity. More particularly in this connection. it. is an object to provide what may be designated a basket weave in a toroid form of coil.

Another feature of the invention relates to the provision of a coil construction which is so arranged as to reduce the amount of dielectric in contact with the turns of the coii to a very tow amount so as to correspondingiy reduce the selt-capacity of the coil. in this connection. it is an object to, at the same time, establish a coil having sutlicient mechanical rigidity and strength to stand up in commercial work and shipment.

More particularly it is an object to establish the supportfor the coil turns by means o the same devices which serve to retain the various turns in their basket weave term.

A further object of the invention is to matte provision for the incorporation of the 't'catur-s ot' the present invention in toroid coils either in the form of ordinary lain inductances or in the firm of trans- In the latter case. provision is formers. made tor the insertion and support of a primary coil centrally placed within the body of the secondary coil. both coils being of toroid term.

Another feature of the invention relates to the provision of an improved method of 1, 1925. Serial NO. 59,795.

winding the coil, and also the provision of a simple coil winding machine for doing this work.

Other objects and uses of the invention will appear from a detailed description of the same, which consists in the features of construction and combinations of parts hereinafter described and claimed.

in the drawings:

Figure 1 shows a side elevation of a completed coil embodying the features of the present invention. the same being carried by a sin'iplc form of support;

Fig shows a vertical cross section on the line 2--2 of Fig. 1, looking in the direction of the arrows;

Fig. 3 shows a side elevation of a coil wound in basket form according to one feature of the present invention, the coil being illustrated in substantially the condition in which it is removed from the winding machine;

Fig. =1 shows a view similar to that of Fig. 3. with the exception that a primary coil has been set into place as would be the case in the manufacture of a transformer proper;

Fig. 5 shows a view of the coils of Fig. 4 after they have been bent around into toroid form and strips of -ane have been woven into place;

Fig, 6 shows a side view of a simple construction of winding machine for winding the coils oi the present invention;

Fig. 7 shows a cross section on the line T-T of Fig. 4;. looking in the direction of the arrows; and

Fig. 8 shows a cross section on the line ta -8 of Fig. (3, looking in the direction of the arrows.

Referring first to Figs. 1 and 2, the toroid coil is designated in its entirety by the numeral 9. It. includes the successive convolutions it) which are of generally circular form. and which couvolutious lie substan tially within diticrent planes radiating out from a common axial center. The turns of the coil are continuously connected together. so that the coil is electrically continuous around the entire circle.

The ditt'ercnt convolutions are individually of substantially the same diameter, and they are ail supported substantially a fixed distance from the common axial center. Consequently. the turns establish a toroid as clearly evident from Figs. 1 and 2,

The coil as a unit is conveniently supported in any suitable manner, as by the use of a pair of center hub blocks 11 and 12, which are circular and of slightly larger size than the axial diameter of the toroid. These hub blocks are drawn together by a center bolt 13, as shown in Figs. 1 and Preferably a bracket plate 1 is secured to the hub support thus established, said bracket plate reaching down at one side of the toroid and then across beneath the same so as to establish a toot or pedestal 15 tor the support of the coil. This bracket plate 14 may at its upper end draw in and lay flat against the hub block 12 and be secured thereto by the through bolt 13. already referred to.

The pedestal 15 is bent upwards and then luielnvards on an angle. as shown at 17. so as to establish in effect a panel board to accommodate the terminal connectors 18. i9. .20 and 21 for the ends ot' the coils. Two of these connectors QtYand 21 are for the two ends of the toroid coil. already ret'erred to and the other two connwtors are tor the ends 01' a. primary coil. slltitlltl such coil be used. In the case of a plain inductance not bein a primary. the connectors 18 and 19 will be dispensed with. and the panel board 17, in such case, may be shortened up and the terminal connectors 20 and '21 placed centrally thereon.

Examination of Fig. 2 in particular will show that the nine portions of the convolutions of the toroid 10 are crisscross in a basket weave. This is done by passing each turn alternately to the inside and then to the outside of the adjoining turns accord ing to the selected form ot weave. It is well understood that tl is t vpe o't' weave tends to reduce the interturn ca' iacity ot the coil. and as tax as I am aware. my present invention is tlr. lii'st instance of the application of this principle to the general torm ot toroid coils.

The various turns of the toroid are retained in the lva liet torn: ot weave in any coi'ivcnient manner. but. tor this purpose, l have illustrat d the encircling strips of reed. 2:2. 23. ll. 2? and 26. which reach around through the central portions ol the convol'. tions oi the tcroid in such a manner as. to establish tl-e desired criss-crossimg; of the suc essive convolutions. and also to establish a satis'hutorv u'ieclanical support tor the turns ot the ltll'llltl.

In the particular weave illustrated. there are live ot' these enrircliiur rings 22. 2;"). 25 and 2t and it will be noted that each (022- volution pas es first to the outside of two of? the rings and then to the inside of the third. These rings are preferably of fibrous material. such as strips of reed or other similar material such as pyrolene. celluloid. etc... having a relatively low dielectric capacity. Furthermore. material of this l ind is relatively flexible and strong and does not break except when bent on very sharp angles, and is. therefore, very well adapted for w .aving into the convolutions ol' the coil during the process of manufacture as well as being well adapted to establish the necessary permanent support when completed.

will le noted from examination of Fig.

1 that the reed may be used in the term of a continuous strip w .ven around through the necesary number of complete turns and through the different convolutimis ot the coil. It will be found, in practice, that a continuous strip of reed material may be wound through the different convolutions and stepped from turn to turn without ditlicult as illustrated in Fig". 1..

In order to give additional rigidity to the coil. 1 meter to bind the convolutions to- ;ret her by the use (it strings or threads 27 and which are carried around through the body 1e toroid and tend to draw the conveliitions tlnrrcot against. the center ring 24. In many ases th use of these strings will he ounil unnecessary.

When it is desired to provide a primary coil. the same may be established in the form of an inside toroid 29. generally of consit erably fewer turns than the outside or main toroid 9.

Ret'erring to Figs. 3, 4c and 5. I will explain one method ot winding the coils and bringing them into the general term of the constrt; .tien illustrated in Figs. 1 and 2. The toroid coil 9 first wound as a substantially straight cylinder. rods. such as 30. being woven through the various convolutions in the proper niaiuier to establish the desired basket weave. It is seen that the convolutions are placed close together in both Figs. 3 and 1. ln Fig. 4 there also illustrated the primary coil 29 which is set loosely through the main toroid 9. In those cas s in wh ch tlr presnit invention is us d onlv in cr-unection with a plain imluctance this priiuarv roil will not be used.

llv removing one of the rods from the coil a strip of reed may be run through spa es so vacated. and then the next rod may be r moved and the end o the reed s rip ru throuh the coil spaces so vacated. In like manner. the vari s remaining ro s mav be sari-e vel 'v removed and the reed ..rip run srcce-s=. .el v through the vacated space 'llu-real'ter the tctl strip may be gradually tightened up until tinallv the entire coil is brought into the desired toroid torm.

During the ahove operation. the end n tions of the toroid will be kept sl ghtly separated from each other. a inoicaied in Fig. 5. and upon completion ot the pri'icci-s of weaving the reec strip into place. the cinivolutions may be evened. out so as to bring the entire toroid into a balanced cond tion a mind the entire circle.

the

In those cases in which a primary coil is used. it may be allowed to rest loosely within the body of the toroid during the above operation, and after the weaving process has been completed, the primary may be stretched out into the complete circle and secured in position to establish a primary toroid coil.

After completing the coil 5) it will generally be desirable to tie a pair of strings around through its int rior por io as indicated at 27 and 28 in Fig. 2. \Vhen a primary used it will rest upon these string" 27 and 28,, and it desired. another string 31 may be passed around through the interior of the primary and then tied so as to hold the convolutions of the primary uniformly and firmly distributed around the circle.

Referring to Figs. 6, 7 and Fl. 1 will now explain the machine therein illustrated for automatically winding the coil 9 up to the condition illustrated in Fig. 3.

This machine includes a longitudinally extending shaft 32 carried in bearings in suitable brackets 33. 34 and 35. Any convenient means may be provided for driving the shaft.

l'pon this shaft is mounted a gear 36 which drives a. pinion 37 on a stun shaft 3.

in a ratio of 3 1/3 to l. lhat is. the shaft 38 makes 3 1/3 revolutions for each revolution of the shaft 32. At its (r er end the stub shaft 38 carries a crank pin 39 which swings a bell crank 4-0 pivoted at the point 4-1, a suitable connection being e tablished between the pin 39 and the hell crank 40 by means of a link 42. The other arm 43 of the bell crank is forked and is connected to a sleeve by a pin and slot connection 45.

Journaled upon the shaft 32 if a spco including the barrel 46 and the end hea 4'? and 48. A collar 4-9 is secured to ii shaft 82 and has a pin 5t) reach ng out in its back face in position to receiv a o. responding socket in the spool ea zl lid. in this way. the spool is .otatrd in harmony with the shaft 32.

l lxtending axially through the two heads 47 and -48 are ten rods or pins dc nated i. 52. 5%. 5L 55. 5t). 5?. 5 fil til Five of these are prov ded with outwardly extending lingers. such ill in l re T. the other live being plain. as shown in said iigure.

The hub ll carries a tlangc G2 to which i secured an inwardly reaching tingcr 61' in position to engage one or the other of the lingers (31 depending upon the position of the. spool. In this connection. it will be noted that as the spool rotates. the pins 51-60 travel therewith. so that the lingers 62 are carried successively past the position of the finger G3.

lVhen the bell. crank is swung the finger till.

63 is drawn to the left and will simultaneously draw back the particular pin which stands in the proper position for engagement of its finger 61 by the finger 63. This will result in the Withdrawal of said pin momentarily from the right hand end of the spool. Normally the Winding of the wire proceeds on the ditl'erent pins. but in case of the momentary retraction of a pin, it is evident that the convolution will at that point fall below the normal level and cause the establishment of a basket weave.

lYhen the bell crank is again restored to the position indicated in Fig. 6., the flange (32 will force back and restore the pin which was so retracted. so that thereafter the winding will proceed on the outside of said pin until it is again retracted.

In order to keep the convolutions in satisfactory order during the winding process, I prefer to place a sliding plate (S t on the spool and pins, the same being slidably mounted with sutiicicnt friction to keep the convolutions closely packed, but nevertheless it allows said plate to slide over as the operation progresses. I also prefer to place another sliding plate on the spool adiaccnt to the position of the hub 47. This plate is provided with a series of buttons (36 which are spring pressed outwards by the spring (37, and their outer enns may be engaged by the flange (S8 of a svinging arm, (3!) pivoted at the point TO. A rod Tl is slidahly mounted in the base 72 and normally retracted by a spring 73 so as to bring its shoe 74 against a finger 75 on the flange 62. i V

A thumb screw 76 on the lever (it) bears against the outer end of the sliding bar 71 and permits the parts to be properly adjusted. As a result the restoring movement of the. sleeve 44 under the impulse of the bell crank serves to force the bar 71 to the right, and thus swing the arm (39 and force the spool head ('35 under spring pressure against the newly wound convolution.

Owing to the tact that the gear ratio be tween the gears 36 and 37 is 3 1/3 to 1. it follows that the bell crank 40 will he swung a complete back and forth movement during 3,10 t a revolution of the shaft 13:2 and the spool. so that the spool will advance the di -iaucc of three rods between complete bell crank swings. As a result. thc finger (33 will also ship at least two of the rods. thus causing the convolutions to stay outside of two rods and drop beneath the third rod during the winding operation.

From the above it will be seen that; l have provided means for automatically winding the basket weave coil in the desired manner. It will also be noted that the basket weave condition is only presented around the inner half of the toroid. If desired. the basket weave could be continnued around the entire Hit surface oi the toroid, including its outer half, but ordinarily this will be nnncces.... and in some respects, may be undesirable.

W'hile I have herein shown and described only certain embodiments of the features of my present invention, still I do not intend to limit myself to the same, except as 1 may do so in the claims.

I claim:

1. As a new article of manufacture, an inductance unit for the purpose specified comprising a continuous coil in the shape of a toroid havinq its convoiutions lying substantially in planes extending substantially radial with respect to its axis, the inner portions of the successive convolutions Cl'iSi-S-Li'OSSlllQ each other within the inner hal t ot' the toroid to establish a basket weave around said inner halt of the toroid, a continuous iength of flexible fibre reed extend ing around the inner half of the toroid and between criss-crosses of successive convolu tions thcrcot within said basket weave portion, a pair ot binding cords extending around the inner portion of the toroid to draw the convoi ions thereof firmly together, another tcroid coil centrally located within the toroid aforesaid. and a cord extending around through the second mentioned toroid coil to draw the same lirmly against the first mentioned cords, substan tially as described.

2. As a new articie of manufacture, an indu tance unit for the purpose specified coniprisin r a continuous coil in the shape ot a toroid having its convolutions lying substantialiv in planes extending substantially radial with r spect to its axis, the inner portions of the successive convolutions criss crossing each other within the inner halt ot the toroid to establish a ba ket weave around said inner halt ot the toroid, a continuous length of flexible tibre reed extending around the inner hall' of the toroid and between the criss-crosscs of successive convolutions thereof within said basket weave portion, and a pair of binding cords extending around the inner portion of the toroid to draw the convolutions thereof firmly together, substantially as described.

3. As a new article of manufacture, an inductance unit for the purpose specified comprising a continuous coil in the shape of a, t rrid having its convolutions lying substantially in planes extending substantially radial with respect to its axis, the inner port s oi the successive convolutions crisscrossing ach other within the inner half of the toroid to establish a basket weave around said inn r ha I oi the t-oroid, and a cont nnous length of flexible iibre reed extending around the inner half or" the toroid and between the crisis-crosses of successive convohnions within said haslvtet weave portion, snhetantially as described.

its a new article of manufacture, an inductance unit tor the purpose specified comprising: a continuous coil in the shape of a toroid having its convolutions lying sobstantiaiiy in planes extending substantially radial with respect to its axis, the nner portions of the successive convolutions mis -crossing excl: other within the inner hal t of the toroid to establish a basket weave around said inner half of the toroid, and means for securing the convolutions in proprr po 'tion with respect to each other. suhstantiaitv as descrihed.

5'. its :1 new article of manufacture, an iiniuctancc unit. tor he purpose specified comprising: a eontiiiiuous coil in the shape of a toroid havingits convolutions lying substantially in planes extending substantially radiai with rtet to its axis, those poriims o the successive convolutions lying in half t the toroid criss-cro ing, each "Ka n said half of the toroid to esv;. weave aroun said halt of he toroid, lilktuittltttly as described.

tii ltilitifi A. LBREEBURG 

